The present invention relates to an arrangement for determining the height of a multilayer stream of articles and maintaining that height to within predetermined levels. More particularly, the arrangement is utilized in combination with a conveyor system having a variable drive that increases conveyor speed when the height is low and decreases conveyor speed when the height is excessive. These conveyor speed adjustments maintain the multilayer stream of articles to within predetermined levels.
In the tobacco industry it is common to convey multilayer streams of rod-shaped cigarette articles from the manufacturing stage to packaging. Moreover, it is common to detect the height of such streams at convenient locations, and to control the conveying speed of the multilayer stream so that the level thereof remains within predetermined limits. U.S. Pat. No. 4,774,840, granted Oct. 4, 1988, discloses a detector of this type and the disclosure thereof is incorporated herein by reference.
Similarly, U.S. Pat. No. 4,641,024, granted Feb. 3, 1987, shows a conveyor system for conveying cigarettes from a cigarette manufacturing machine along a plurality of channels to a packaging machine. The level of the cigarettes in one or more of the channels is measured by an analog-type level detector which generates a continuous output signal used to continuously control the speed of the convey system.